.box-left{
    border: 1px red solid;
    display: flex;
    float: left;
    flex-direction: column;
}
.box-right{
    border: 1px red solid;
    float: left;
    display: flex;
    flex-direction: column;
}
.box{
    border: 1px red solid;
}

.clear{
    clear:both;
    margin: 0;
    padding: 0;
}